SMRs & the GDA Process

What Are SMRs and How Do They Compare to NPPs?

Like NPPs, SMRs are advanced nuclear reactors. SMRs closely mirror their larger NPP parents, but are designed to be smaller in size. This difference in size gives rise to a number of key features which sets them apart from the traditional NPP model:

• Scalability: Traditional NPPs are often built with large capacities, intended to power large cities. SMRs by contrast generally have capacities of less than 300MW(e) per unit, which is roughly 1/3 of the capacity. SMRs can therefore be small and more flexibly deployed, for example, in remote areas with modest power requirements, or in communities which do not have lots of spare land. Some SMRs have capacities as low as 10MW(e) (“Microreactors”) meaning a (comparatively) tiny footprint. This also makes SMRs well-suited for connection to larger pre-existing plants, to make use of existing outputs and convert those into further useful energy, such as heating.
• Cost Efficiency: Due to their size and complexity, NPPs require substantial upfront capital investment and long payback periods. SMRs however, by virtue of their modular nature, can be built in factories, which in turn can achieve economies of scale and standardisation. SMRs usually require lower upfront investment, and can be fabricated offsite with shorter construction timelines.
• Maintenance: SMRs usually require refuelling approximately every 3-7 years, while NPPs require refuelling at 1-2 year intervals.
• Stability of the Grid: Due to their size, SMRs can also be used to complement intermittent renewables like wind and solar by providing reliable baseload power which operates, for example, overnight, on cloudy days, or on days without wind.
• Enhanced Safety: Many SMR designs employ passive safety systems that rely on natural processes, such as gravity and convection, to cool the reactor core in case of emergencies, which eliminates the need for active intervention.

SMRs in the Wild

Some SMRs are already in operation. For example, two KLT-40S SMRs (each a 35MW(e) pressurised water reactor (“PWR”)) are used in the Akademik Lomonosov – the first floating nuclear power plant.¹ The Akademik Lomonosov is docked in Pevek, Russia, where it provides heat and electricity to the town. The movable nature of the Akademik Lomonosov makes it an interesting option for Arctic communities, which are often extremely rural and hard to reach.

More are being built; Westinghouse Electric Company announced recently that it had signed an agreement for the construction of four of its AP300 SMRs at a site in North Teeside, UK.² The AP300 is also a PWR, with a capacity of 330MW(e).³

Regulation in the UK

In the UK, design proposals for SMRs should first undergo the generic design assessment (“GDA”) process. This is a three-step process developed by the UK Environment Agency (“EA”), Office for Nuclear Regulation (“ONR”) and Natural Resources Wales (“NRW”). The aim of the GDA is to give greater structure and clarity to developers of nuclear energy infrastructure designs, but also to ensure that designs meet the required standards for safety, security, environmental protection and waste management, sustainability, and other additional safeguards.⁴

Step 1: Initiation (12 months)

First, the GDA process must be formally initiated by the Department for Energy Security and Net Zero (DESNZ). The requesting party (“RP”, i.e. the party with the design to be assessed) then liaises with the ONR and EA to agree the parameters of the GDA to be undertaken. This usually includes discussions on whether the RP has, amongst other things, established full project management and technical teams; an adequate design development process; and appropriate nuclear waste disposal plans. Once agreed, a GDA Step 1 Statement is issued, setting out the scope of the GDA, including the regulatory position and criteria which a design will have to meet.

Step 2: Fundamental Assessment (12 months)

The ONR and EA then undertake a high level assessment of the proposal against the relevant regulatory requirements to identify any gaps in the RP’s planning. As RPs undergo Step 2 of the GDA process (and Step 3), they must provide certain information about the proposed design on a publicly accessible website, including information regarding how the design will meet the relevant standards for environmental protection, safety, and security. At the end of Step 2, a GDA Step 2 Statement is issued, setting out the findings of the Fundamental Assessment and whether any further work is required to bring the proposed design in line with UK regulations.

Step 3: Detailed Assessment (24 months)

Third and finally, a Detailed Assessment of the proposed design is undertaken. The Detailed Assessment is a much deeper dive into the design and the environmental plans the RP has put in place and will ultimately decide if a proposed design is compliant with the relevant UK regulations. There will also be a public consultation on the proposed design and findings of the GDA process so far. At the end of Step 3, a decision on the design proposal is issued, determining whether the project should proceed to construction.

Westinghouse completed the GDA process for its AP300 earlier this year,⁵ while Rolls Royce recently completed Step 2, and made its GDA website live.⁶

Challenges and Considerations

While SMRs hold immense promise, they are not without challenges. Regulatory approval, public acceptance, and nuclear waste management remain significant hurdles. Concerns regarding proliferation, security, and the potential for accidents must be also addressed through robust regulatory frameworks and stringent safety protocols.

The economics of SMRs depend heavily on factors such as construction costs, regulatory requirements, and market conditions. Achieving widespread commercialisation will require concerted efforts from governments, industry stakeholders, and research institutions to overcome technical, regulatory, and financial barriers.

¹ https://fnpp.info/about.

² https://info.westinghousenuclear.com/news/westinghouse-and-uks-community-nuclear-power-collaborate-to-deploy-fleet-of-ap300-small-modular-reactors.

³ https://westinghousenuclear.com/energy-systems/ap300-smr/.

⁴ https://www.gov.uk/government/publications/new-nuclear-power-plants-generic-design-assessment-guidance-for-requesting-parties/new-nuclear-power-plants-generic-design-assessment-guidance-for-requesting-parties#the-gda-process.

⁵ https://info.westinghousenuclear.com/news/westinghouse-ap300-small-modular-reactor-approved-for-united-kingdoms-generic-design-assessment.

⁶ https://gda.rolls-royce-smr.com/.